Whether hunting game or merely target shooting with a bow and arrow the problem of accurately sighting the target still exists. This is due principally because the trajectory of an arrow is substantially flat for only a relatively short distance. This distance when the arrow trajectory is about flat (commonly called the "dead on distance") is approximately 20 to 35 yards for most bows. The "dead on distance" is dependent upon the particular bow and especially its pull or poundage If the archer knows the distance to the target, there are quick adjusting sights that are reasonably accurate An example of such a bow sight is shown in Frydenlund U.S. Pat. No. 3,487,548. However, especially when hunting live game, the distance to the target is not known and must be estimated, and if the estimate is not reasonably accurate, the sight will not provide for an accurate hit. To aid the archer in these situations, there are available range finders which will provide a reasonably accurate measurement of the distance. In some instances, the range finder is combined with the sight, but this still requires the archer to first determine the range, and once determined, use the sight before releasing the arrow. This obviously involves two steps, and when hunting live game, the archer may not have the time to go through these two steps. An example of a combination range finder and bow sight is shown in Larson U.S. Pat. No. 3,696,517.
In an effort to overcome the disadvantages of the foregoing types of bow sights, there have been attempts to develop combination range finders and bow sights that will more readily and accurately assist the archer in providing an accurate sight of the target. Sprandel U.S. Pat. No. 3,666,368, Davidson U.S. Pat. No. 3,875,674 and Stuchnick U.S. Pat. No. 4,418,479 are examples of attempts at providing a sight that will be accurate over a considerable range from the archer to the target. However, these prior art devices are relatively complex and expensive and not easy to use. There is therefore a need for a simple, inexpensive and easy to use bow sight which will automatically compensate for differences in the distance between the archer and the target.